> Thanks,
>
> Mathieu
>
> * tip-bot for Li Zefan (
lizf@cn.fujitsu.com) wrote:
> > Commit-ID: 3656d5431262ca25aba01d08a5b6e1295ab8feeb
> > Gitweb:
http://git.kernel.org/tip/3656d5431262ca25aba01d08a5b6e1295ab8feeb
> > Author: Li Zefan <lizf@cn.fujitsu.com>
> > AuthorDate: Wed, 24 Mar 2010 10:57:43 +0800
> > Committer: Steven Rostedt <rostedt@goodmis.org>
> > CommitDate: Fri, 26 Mar 2010 15:30:21 -0400
> >
> > tracing: Remove side effect from module tracepoints that caused a GPF
> >
> > Remove the @refcnt argument, because it has side-effects, and arguments with
> > side-effects are not skipped by the jump over disabled instrumentation and are
> > executed even when the tracepoint is disabled.
> >
> > This was also causing a GPF as found by Randy Dunlap:
> >
> > Subject: 2.6.33 GP fault only when built with tracing
> > LKML-Reference: <4BA2B69D.3000309@oracle.com>
> >
> > Tested-by: Randy Dunlap <randy.dunlap@oracle.com>
> > Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> > Cc:
stable@kernel.org
> > Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
> > LKML-Reference: <4BA97FA7.6040406@cn.fujitsu.com>
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> > ---
> > include/linux/module.h | 6 ++----
> > include/trace/events/module.h | 14 +++++++-------
> > kernel/module.c | 3 +--
> > 3 files changed, 10 insertions(+), 13 deletions(-)
> >
> > diff --git a/include/linux/module.h b/include/linux/module.h
> > index 5e869ff..393ec39 100644
> > --- a/include/linux/module.h
> > +++ b/include/linux/module.h
> > @@ -460,8 +460,7 @@ static inline void __module_get(struct module *module)
> > if (module) {
> > preempt_disable();
> > __this_cpu_inc(module->refptr->count);
> > - trace_module_get(module, _THIS_IP_,
> > - __this_cpu_read(module->refptr->count));
> > + trace_module_get(module, _THIS_IP_);
> > preempt_enable();
> > }
> > }
> > @@ -475,8 +474,7 @@ static inline int try_module_get(struct module *module)
> >
> > if (likely(module_is_live(module))) {
> > __this_cpu_inc(module->refptr->count);
> > - trace_module_get(module, _THIS_IP_,
> > - __this_cpu_read(module->refptr->count));
> > + trace_module_get(module, _THIS_IP_);
> > }
> > else
> > ret = 0;
> > diff --git a/include/trace/events/module.h b/include/trace/events/module.h
> > index 4b0f48b..a585f81 100644
> > --- a/include/trace/events/module.h
> > +++ b/include/trace/events/module.h
> > @@ -53,9 +53,9 @@ TRACE_EVENT(module_free,
> >
> > DECLARE_EVENT_CLASS(module_refcnt,
> >
> > - TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
> > + TP_PROTO(struct module *mod, unsigned long ip),
> >
> > - TP_ARGS(mod, ip, refcnt),
> > + TP_ARGS(mod, ip),
> >
> > TP_STRUCT__entry(
> > __field( unsigned long, ip )
> > @@ -65,7 +65,7 @@ DECLARE_EVENT_CLASS(module_refcnt,
> >
> > TP_fast_assign(
> > __entry->ip = ip;
> > - __entry->refcnt = refcnt;
> > + __entry->refcnt = __this_cpu_read(mod->refptr->count);
> > __assign_str(name, mod->name);
> > ),
> >
> > @@ -75,16 +75,16 @@ DECLARE_EVENT_CLASS(module_refcnt,
> >
> > DEFINE_EVENT(module_refcnt, module_get,
> >
> > - TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
> > + TP_PROTO(struct module *mod, unsigned long ip),
> >
> > - TP_ARGS(mod, ip, refcnt)
> > + TP_ARGS(mod, ip)
> > );
> >
> > DEFINE_EVENT(module_refcnt, module_put,
> >
> > - TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
> > + TP_PROTO(struct module *mod, unsigned long ip),
> >
> > - TP_ARGS(mod, ip, refcnt)
> > + TP_ARGS(mod, ip)
> > );
> >
> > TRACE_EVENT(module_request,
> > diff --git a/kernel/module.c b/kernel/module.c
> > index c968d36..21591ad 100644
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -800,8 +800,7 @@ void module_put(struct module *module)
> > preempt_disable();
> > __this_cpu_dec(module->refptr->count);
> >
> > - trace_module_put(module, _RET_IP_,
> > - __this_cpu_read(module->refptr->count));
> > + trace_module_put(module, _RET_IP_);
> > /* Maybe they're waiting for us to drop reference? */
> > if (unlikely(!module_is_live(module)))
> > wake_up_process(module->waiter);
>
